The invention relates to a piston and cylinder unit comprising a piston adapted to be displaced in the axial direction, a piston rod arranged coaxially and connected with the piston on at least one axial face thereof and which extends through an associated cylinder and cover in a sealing and sliding manner, the section of the piston rod outside the cylinder being able to be connected with load attachment means.
In the prior art piston and cylinder units have been designed so that the piston rod is made of solid material and for fixation of the piston and of the load attachment means the two axial ends of the piston rod have male threads cut into them. The consequence of this is a relatively high weight of the piston rod and this increases inertia and means that high piston acceleration is not possible in all cases. Furthermore it is a disadvantage that for matching different load attachment means and different pistons it is necessary to have different piston rods which have different sizes of male thread so that in order to provide for a reasonably wide range of products extensive stockholding and high warehouse costs are involved. If furthermore the threaded piston rod sections are to have a high strength, the entire piston rod has to be made of high quality steel, something that very considerably increases the costs of production.